Doctrine_Cache offers many options for performance fine-tuning:
<ul>
<li \> savePropability <br \>
Option that defines the propability of which
a query is getting cached.
<br \><br \>
<li \> cleanPropability <br \>
Option that defines the propability the actual cleaning will occur
when calling Doctrine_Cache::clean();
<br \><br \>
<li \> statsPropability
<ul \>